Electrical fire-alarm system.



J. H. FIELD.

ELECTRICAL FIRE ALARM SYSTEM. APPLIOATION FILED FEB.3, 190 9.

976,645 Patented Nov. 22, 1910 "ma l. -f f v i v a UNITED STATES PATENToFFIoE-Q JAMES .HASLIP FIELD, OF VICTORIA, BRITISH COLUMBIA, CANADA,ASSIGNOR TO THE CANADIAN TAYLOR AUTOMATIC FIRE ALARM AND OF VICTORIA,CANADA, A CORPORATION.

CALL BELL COMPANY, LIMITED,

ELECTRICAL FIRE-ALARM SYSTEM.

To all whom it may concern:

Be it known that I, JAMES HASLIP FIELD,

a subject of the King of Great Britain, rev siding at Victoria, in theProvince of British Columbia, Canada have invented new and usefulElectrical ire-Alarm Systems, of

' which the following is a specification.

This invention relates to an electrical fire alarm system of that classwherein an opencircuit is closed or a closed circuit-opened to ring analarm by thermostats when the temperature surrounding any one of themrises consequent on abnormal conditions beyond that for which it hasbeen set.

The invention has been particularly de-- signed for application to 'afire. alarm system wherein the thermostat contact is used in conjunctionwith the pushbuttonof an ordi-. nary electrical call'system where thetherinostat instead of being'on the ceiling, where any abnormalelevation of temperature in a room would naturally first be felt,

is necessarily placed on the wall at a con-- venient height for theoperation of the push button. Under these conditions the thermostatrequires to be much more sensitive to a rise of temperature in order toget-effective service from it as a fire alarm. VVhenhowever thethermostats are so' sensitive that they will act under the conditionsnamed:

they are extremely liable to act under daily fluctuations of heat, andit is to guard against'this contingency that the invention which is thesubject of this application has been devised. j

I overcome the difficulty by placing in the circuit, in some positionwhere it will be subject to the same general conditions of temperatureas those in the line, a master thermostat so adjusted that it will actto open or close the circuit, according as it is a normally open or anormally closed circuit system, at a temperature slightly less than thatfor which the thermostats of the circuit are adjusted; sothat if thegeneral tem perature is such that it mightoperate any one of 'thecircuit thermostats to ring an alarm thesame general rise of temperaturewould operate the master'thermostat to open or to close the circuit 'asthe case. may be to prevent that alarm being rung. A general rise intemperature will thus not permit an alarm to be rung by anyone of theseSpecification of -Letters 1 atent.

Patented Nov. 22, 1910.

'r' maaon filed February 3, 1909. Serial no. 475,814.

delicately set thermostats, but a local rise though slight as in theinitial stage of a life inany room .or part of the building will ring analarm, as the master thermostat which controls the circuit will not havebeen acted upon to open or close it as the system in use may require.

In the application of the system there are several features ofarrangement incidental to its use to which attention will be called inthe course of the following specification.

which fully describes various applications of the system, referencebeing made to the drawings by which it is accompanied, in

which: I

Figure 1, illustrates diagrammatically the application of a masterthermostat to control a. simple open circuit, Fig. 2, shows va practicalapplication of the principle to-an open circuit thermostat system Fig.3, the

application; of a master thermostat to control a closed circuit system,and Fig. 4:, a

portion of a circuit in which the master .of the operatingbattery 6 by awire .3 and the contacts 8 by wires 7 to the other pole of the batteryeach wire passing through the coil of its .annunciator. Thus if anythermostat is brought into engagement with its contact 8 either manuallyor by the necessary rise iii temperature the circuit is closed and thealarm bell rung while'the location of the thermostat at which contacthas been made is announced. As the association of a push button with a.thermostat necessitates the thermostat being placed on the. wall it willrequire to be adjusted to act at a temperature less than that at whichit would be set were it p'laced in the ceiling of a room. Toprevent aslight general rise of temperature, and therefore presumably one thatrepresentthe line therits does notnecessitate an alarm, from ringingsuch alarm, a master thermostat is introfor which the line thermostatsare setso that duced 'in the common wire ofthe circuit which thermostatis normally closed on;

its contact but is adjusted to break contact at a temperature slightlyless than that before a general rise of temperature over the wholesystem can ring in a false alarm the master thermostat will have openedthe circuit and will prevent such alarm being given. This illustratesthe principle under which the master thermostat is introduced but thediagram does not represent a practical'working system for it .will beobvious that by a general rise in temperature such as to act upon themaster thermostat to open thecircuit the system is rendered useless foreither a call bell or alarm. 4 Fig. 2 represents a'practical' workingsystem in whichthe objection just referred tO'IS overcome: In iteachthermostat 2 is provided.with' a secondary contact 11 whichis connectedthrough. a separate. wire 12 through aseparate coil on the annunciator4- to the battery 6 and the master thermostat 10 is introduced in thecommon wire which connects the several wires 7 before such common wireof 7 is joined by the common wire of the secondary contacts 12. Thismaster thermostat is as' before normally closed but will open thecircuit to prevent a false alarm being rung if a slight'general rise oftemperatureoccurs, such as would, acting on the line thermostats 2 bringthem into engagement with. their contacts 8; but'if a thermostat 2 ismanually closed by its push button or if a further rise of temperatureoccurs l'oca-lly'such as might be occasioned 40 by an incipient fire,the thermostat 2 will engage its secondary contact ll-to close thecircuit, and as the connection 12 from each of the secondary contacts,after passing through its own annunciator coil is connected on thebattery side of the master thermostat 10 its circuit has not been openedeach though in practice one thermostat only may be used and the contactswill have such -resi lience' as will allowthe thermostat to moveofifirst one and then the other. As the operation of the contacts of theline circuit and its alarm bell circuit are practically the same, theconnections and parts which perform similar functions are similarlynumbered in each circuit but the line circuit the closed line circuitand the lower part in finer lines the alarm bell circuit; ,though itmust be understood in applying this system that the relays of thes'everalcontacts may be placed adjacent to their annuneiators and thealarm bell.

The line thermostats 2' are connected by 3 to one pole of the battery 6and the primary and secondary contacts 8 and 11 by 7 and 12 respectivelyeach through the coil of separate relays 15 and 16 t0 the other pole ofthe battery. With this arrangement whilethe line circuit is n'brmallyclosed, an elevation of temperature beyond that for which the linethermostats are adjusted to break from their contacts will cause thebattery circuit to be broken and the relay armature of the actingthermostatreleased.

The armatures 17 and 18 of the primary and secondary relays 15 and 16are connected by 3 through the alarm bell to one pole of its battery 6and when released from their respective relay magnets will fall intoengagement with contacts 8 or 11 which are connected by 7 and 12 throughseparate coils of the annunciators' 4 to the other aoleof the battery.In the common wire of t 1e connection 7 to the battery 6 is placed themaster thermostat 10, normally closed as before andadjusted .to breakthe circuit at a temperature slightly below that for which the linethermostats are adjusted to break from their primary contacts. Thecommon wire '12 front-the secondary contacts is, after passing throughthe coils of the annunciator,

connected to the common wire 7 of the pri mary coils at a point betweenthe master thermostat and the battery. \Vith this a'rrangement? when theline thermostats are exposed to a general rise of temperature above.

that for which they are adjusted and break from theiij' primary contacts8, their relay,

armatures 17 are released to close the alarm bell circuit fbut the alarmcannot ring because the bell circuit has been broken by the masterthermostat 10 which may be assumed to have been exposed-to the samegen-- eral rise ofitemperature. Butif while this condition prevails theline circuit is broken at any secondary contact either by a manualapplication or by the exposure of that thermostat to a 'suflicienttemperature the armature 18 of the relay 16 is released and by contactwith 11 closes the alarm bell circuit, as the connection 12 of thiscircuit joins the common wire, between the master thermostat and thebattery and thecircui-t has not therefore been interrupted by the actionof the master thermostat.

The master thermostat has so far been described-as acting'to open anormally closed 'the closed circuit system illustrated in Fig.

3 where a master thermostat normally open is introduced in a connectionbetween 3 and '1', between the contact 8 and the relay 1:). Thisthermostat being normally open will close before the line thermostatbreaks from its primary contact 8 and close a substitute circuit for thecurrent through the relay which will .therefore hold its armature 17 tomaintain open the alarm bell circuit.

'lVith such an arran ement a master thermostatwill require to befurnished for each line thermostat or loop in whlch a group ofthermostats may be connected to one annunciatOl.

Although in the foregoing specificationditlerent systems have beendescribed where in the master thermostat has been applied it must not beassumed that the application of 'the master thermostat is to be confinedto such systems; as my invention comprises the application of a masterthermostat to control the action of the line thermostats where theywould operate to ring an alarm by a slight general elevation oftemperature and to'the means for preventing that action of the masterthermostat from preventing an alarm being rungwhen the rise oftemperature has not been general or when a further elevation has beenattained or the contact operated manually.

Having now particularly described my invention and the manner of itsoperation what I claim as new and desire to be protected in by LettersPatent is:

1. In an electrical alarm system of the character described, an alarmbell and battery connected in series therewith, a plurality of generalthermostats in circuit with said batteryand bell for operating the-same,and a master thermostat cooperating with tery and magnets, an alarmcooperatively connected with .the aforesaid parts to be controlled bysaid general thermostats, and thermostatic means cooperating with theaforesaid parts to render the said general thermostats inoperative underpredetermined cond1t1ons. i 4

3. In an alarm bell system, an open cir cuit including an alarm andgeneral thermostats together with a source of electric energy therefor,said thermostats operating to close said circuit when the temperature isattained, for which they have been adjusted, a master thermostatcooperating with the aforesaid parts which normally closes the circuitbut, at a temperature slightly below that for which the generalthemostats have been set, will open the circuitand prevent the alarmbeing rung.

4. In an electrical alarm systembf the class described wherein isprovided ag alarm circuit and a source of electric energ therefor, andline or general thermostats in said alarm circuit for controlling theringing of said alarm, means. for preventing the operation of thegeneral thermostats under predetermined conditions, said meanscomprising a master thermostat cooperating with the aforesaid parts thatwill also control the ringing of an alarm under predeterminedconditions.

In an electrical alarm system of the class described, a battery circuit,thermostats having prnnary and secondary contacts connecting with saidbattery circuit and a thermostatically controlled member also connectedwith said battery circuit for engaging said contacts at differenttemperatures,-a master thermostat in the connection -of the primarycontacts with the battery circuit that will open that connection at aterm perature slightly less than that for which the line thermostats areset and that will not break the circuit connecting the secondarycont-acts to the battery.

6. In an electrical alarm system the combination with a circuit in whichis abattery and alarm bell, of line thermostats connected to one pole ofthe battery each thermostat having primary and secondary contacts whichmay be adjusted to be engaged by the thermostat at differenttemperatures, means for connecting the primary and secondary contacts tothe other pole of the battery, and a master thermostat in the connectionfrom the primary contact that will open the circuit at a temperatureslightly less than that at which the line thermostats are set to closeonto their primary contacts.

A. WooLsEY.

